1. Field of the Invention
The present invention relates to therapeutic conjugates of a drug or modified toxin and a protein which reacts with a substance associated with a targeted cell which internalizes the conjugate into the cell.
The present invention also relates to improved and optimized methods for site-specific conjugation of antibody or antibody fragments with toxins or drugs.
The present invention further relates to compositions and methods useful in cancer therapy.
The present invention further relates to compositions and methods useful in viral, microbial and parasitic therapy.
2. Description of the Prior Art
Drugs and toxins which are internalized into a cell are extremely potent cytotoxic agents of cells that are responsible for many human diseases. Because of their high activity, these agents have been attached to monoclonal antibodies in order to form cytotoxic agents which specifically bind to target cells. These immunotoxins are, therefore, very useful in therapy for cancer, viruses, parasites, and other infectious organisms.
Various methods have been used to attach toxins and drugs to monoclonal antibodies; however, a need continues to exist for a site-specific method to form a stable conjugate of a protein, particularly, an antibody or antibody fragment, and a toxin or drug having a therapeutic effect similar to that of a toxin.